ASoC: wcd934x-dsp-cntl: add ramdump support

Add support to collect the codec memory dumps when any fatal
interrupt is raised from the DSP indicating the DSP is either
unresponsive/crashed. The memory dumps are only collected if
the debugfs node 'ramdump_enable' is set to true since ramdump
collection is debug only support.

Change-Id: I805ec63d125770b869cac892db8cf56f45510d6d
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>